The invention is a system and method for measuring rotor blade movement in a turbine engine. More particularly, for measuring the arrival time and thickness of a rotor blade during engine operation.
During operation of a gas turbine engine, rotor blades are placed under stress by the operating environment. To best maintain the engine in proper operational condition, the rotor blades are monitored to detect any weakening over time. Specifically, the vibration modes of the rotor blades are monitored to expose any twisting and vibrations, or flutter, of the blades during engine operation.
However, known monitoring equipment have difficulties withstanding the heat of the turbine engine environment. Thus, measuring the vibration modes of rotor blades is difficult in sections of the turbine engine that operate under high temperatures. Known methods of measuring vibration modes involve using optical sensors or eddy current sensors. These methods have a disadvantage since the measurements and testing may only take place at cooler temperatures that may not accurately represent the rotor blades during actual engine operation. As a result of not being able to measure vibration modes during engine operation the system is reliant on an operator or mechanic to schedule routine testing of the rotor blades.
Additionally, known systems measure the vibrations modes of the rotor blades by monitoring the passage of a blade. Passage of the blade provides information regarding flutter. However, additional data is desirable to calculate the twisting of the rotor blades. In the prior art, multiple probes must be placed along the chord of the blade to provide the data needed.
Reflected signals have been utilized in analyzing turbine blades, but not for vibration analysis.
An arrangement and method for measuring vibration modes of rotor blades during operation of a turbine engine is needed.